raghadalhebsi1204 raghadalhebsi1204
  • 01-09-2020
  • Biology
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Why is chalk used on blackboards?

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knation911 knation911
  • 01-09-2020
A blackboard, also called a chalkboard, is a surface on which markings made with chalk are visible. Whiteboards are used because some people are allergic to the dust the chalk used to write on chalkboards generate, and because the dust is hard to clean up when spilled.
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